To demonstrate the role of justice, Hume paints a picture of a world in which everyone has all they could wish for and there's no envy, resentment, or need for justice and property laws. This may seem like a fantasy world, but Hume explains that, even today, when something is freely available (such as air and water) we don't create rules about property. It's only when things are in short supply that rules need to be set up.
Some folk have defended the liberty of the seas on the same grounds. However, since the advantages gained by navigation aren't limitless, rivalry rears its head and we start to see how problems can arise...
Hume recognizes the bond that people can feel with their loved ones, with this bond overriding rules of property.
He adds that some folk have tried to build communities that operate in a similar way and have only adopted rules of justice and property when they've found that it wasn't working. Hume's point? Justice only arises when it's useful (in case you haven't noticed, you'll be hearing this word a lot).
To demonstrate this, Hume imagines a scenario in which resources are no longer plentiful and everyone's seriously gloomy. In this case, Hume suggests that people's self-preservation instincts are likely to kick in. After a shipwreck, for example, people's priority is to take hold of whatever they can to ensure their survival. Hey, desperate times call for desperate measures (turns out that even Wilson has a dark side).
Hume sees war as another suspension of justice. Whenever justice no longer offers any advantage, it's overtaken by other concerns.
Now, Hume tackles the question of how and why rules of property and justice have been invented and become so widespread. Hume points out that societies don't usually operate at the extremes mentioned above, but instead occupy a middle ground. Our main interests may lie with ourselves and those close to us, but we learn that keeping up with wider society can be useful too.
The idea of a benevolent society in which everyone looks out for everyone else may have its appeal (just ask the Care Bears). Poetry, for instance, can depict a world in which the weather's perfect, natural resources are in full supply, and no one suffers or causes suffering—a world in which rules of justice aren't needed.
Hume mentions the poetry of the Golden Age as a prime example, contrasting it with philosophical fiction that explores the State of Nature. In this philosophical account, humans began as violent savages who had to rely on themselves. There were no laws, property, or systems of justice, but the result wasn't love and hugs—it was nonstop war. Oops.
Whether humans could live (or continue to live) in this way is something that Hume doubts. As he notes, people are usually raised by their families to recognize appropriate behavior. Still, if this state of ongoing war and violence were real, Hume would see it as another scenario in which the laws of justice would be abandoned.
Hume then sketches out another imaginary scenario in which, as well as us, there's another species of creatures that are weak in body and mind. Hume emphasizes the inequality of this arrangement—humans would wield total authority, our compassion being the only thing keeping us in check. Hume compares this to the way that some groups (e.g., women and people of different races or nationalities) have been treated, though Hume adds that women have often been able to share in society's rights and privileges. So, it's not all bad.
Hume ends by giving us another imaginary scenario in which each person lives wholly for himself or herself and there's no society. But what happens if nature takes its course and families start to emerge? And what if several families come together to form a society? Finally, what happens if a bunch of societies decide that it's a good idea to work together? Can you see where we're going with this? Following this train of thought helps explain how society as we know it today came into being.